In a storage system (such as a Storage Area Network or SAN) there can be clustered node host entities (such as a SAN Volume Controller or SVC) each with multiple I/O initiators that submit I/O. There can also be storage subsystems with multiple I/O targets that export Logical Unit (hereinafter referred to as LU) resources that service I/O requests made by the initiators.
It is known in the art to have a mechanism for coordinating LU access to prevent the performance impacts of accessing the same LU through multiple targets (known as LU thrashing). This technique requires the clustered nodes to communicate with each other to select a single target that all clustered node I/O requests for a single LU are submitted to.
However, in clustered arrangements having grouped storage LUs, there remain significant problems when asymmetric error conditions cause performance impacts on I/O activity.